Sentence arrangement: choose the most logical order of the labelled sentences P, Q, R and S to form a coherent paragraph explaining what recycling is and why it is needed to conserve limited natural resources.

Introduction / Context:
This para jumble question focuses on recycling and the conservation of natural resources. The four sentences talk about the limited nature of earth's resources, define recycling, explain how recyclable products are converted, and emphasise that recycling reduces waste for present and future generations. The test is whether you can recognise a logical flow from problem statement to explanation and benefit.

Given Data / Assumptions:
S says that natural resources on earth are limited and therefore we must conserve, recycle and reuse whenever possible.
P explains that recycling involves turning used materials labelled as recyclable over to a facility so that they can be reused for a new purpose.
R adds that a recyclable product is turned back into a raw form that can be used to create a new and different product.
Q notes that not only are natural resources limited, but recycling efforts can reduce waste that would harm the planet today and in the future.
We assume all four sentences belong to one explanatory paragraph about recycling.

Concept / Approach:
A clear expository paragraph on an environmental topic typically begins with the big idea or problem, then moves to definitions, then to more technical detail and finally to a statement of benefits or consequences. Here, the main problem is limited natural resources. The sentences that provide definitions and mechanisms for recycling should follow this problem, and the sentence that stresses ongoing benefits will likely appear near the end.

Step-by-Step Solution:
Step 1: S is a broad statement about natural resources and the need to conserve, recycle and reuse. This clearly works as an introductory sentence that sets the context. Step 2: After S has introduced recycling as one required action, P should naturally appear because it defines what recycling basically involves in practical terms, namely turning used materials over to a facility for reuse. Step 3: R then continues the explanation by describing what happens at a deeper level: the recyclable product is converted back into a raw form that can be used to create something new. R is thus a more technical follow up to P. Step 4: Q is best placed last. It reinforces the opening idea that natural resources are limited and adds the conclusion that recycling efforts can significantly reduce additional waste, protecting the planet for current and future generations. Step 5: Putting these together gives S P R Q, which corresponds to option SPQR.

Verification / Alternative check:
When we read SPQR as a paragraph, it sounds like a well structured explanation. The author starts by telling us that resources are limited and that we must conserve and recycle. Then we are told what recycling looks like in daily life, followed by what happens to recyclable materials on a technical level. Finally, the writer sums up by connecting limited resources and recycling to the reduction of harmful waste. There is a smooth progression from problem to solution and benefit, confirming the correctness of SPQR.

Why Other Options Are Wrong:
Option PRSQ starts with P, defining recycling without first mentioning why it is needed, and ends with Q before S, which makes the opening about limited resources appear late and breaks the flow. Option RPQS starts even more abruptly with R, a technical point about raw forms, and then jumps irregularly through the remaining ideas. Option PSQR begins with the definition in P and then moves back to S, which should have introduced the paragraph, so the order feels reversed. The additional option SRPQ places Q too early and separates P and R, which both belong together as a pair of explanatory sentences.

Common Pitfalls:
A frequent mistake is to treat Q as a natural opener simply because it restates that natural resources are limited and talks about recycling. However, S states the same limitation in a more direct way and also includes the imperative to conserve, recycle and reuse, making it the stronger introduction. Learners also sometimes feel that technical details should always come last, but in expository writing those details often appear in the middle, followed by a concluding sentence about long term effects.

Final Answer:
The correct logical order of the sentences is SPQR, so option SPQR is the right answer.